Arthur Prior and medieval logic

Though Arthur Prior is now best known for his founding of modern temporal logic and hybrid logic, much of his early philosophical career was devoted to history of logic and historical logic. This interest laid the foundations for both of his ground-breaking innovations in the 1950s and 1960s. Because of the important r?le played by Prior??s research in ancient and medieval logic in his development of temporal and hybrid logic, any student of Prior, temporal logic, or hybrid logic should be familiar with the medieval logicians and their work. In this article we give an overview of Prior??s work in ancient and medieval logic.     

Bolzano and Kant on the Nature of Logic

Here I revisit Bolzano's criticisms of Kant on the nature of logic. I argue that while Bolzano is correct in taking Kant to conceive of the traditional logic as a science of the activity of thinking rather than the content of thought, he is wrong to charge Kant with a failure to identify and examine this content itself within logic as such. This neglects Kant's own insistence that traditional logic does not exhaust logic as such, since it must be supplemented by a transcendental logic that will in fact study nothing other than thought's content. Once this feature of Kant's views is brought to light, a much deeper accord emerges between the two thinkers than has hitherto been appreciated, on both the nature of the content that is at issue in logic and the sense of logic's generality and formality.     

Infinity and a Critical View of Logic

Abstract

The paper explores the view that in mathematics, in particular where the infinite is involved, the application of classical logic to statements involving the infinite cannot be taken for granted. L. E. J. Brouwer’s well-known rejection of classical logic is sketched, and the views of David Hilbert and especially Hermann Weyl, both of whom used classical logic in their mathematical practice, are explored. We inquire whether arguments for a critical view can be found that are independent of constructivist premises and consider the entanglement of logic and mathematics. This offers a convincing case regarding second-order logic, but for first-order logic, it is not so clear. Still, we ask whether we understand the application of logic to the higher infinite better than we understand the higher infinite itself.     

Dual Intuitionistic Logic and a Variety of Negations: The Logic of Scientific Research

We consider a logic which is semantically dual (in some precise sense of the term) to intuitionistic. This logic can be labeled as “falsification logic”: it embodies the Popperian methodology of scientific discovery. Whereas intuitionistic logic deals with constructive truth and non-constructive falsity, and Nelson's logic takes both truth and falsity as constructive notions, in the falsification logic truth is essentially non-constructive as opposed to falsity that is conceived constructively. We also briefly clarify the relationships of our falsification logic to some other logical systems.     

Johnson and the Soundness Doctrine

Why informal logic? Informal logic is a group of proposals meant to contrast with, replace, and reject formal logic, at least for the analysis and evaluation of everyday arguments. Why reject formal logic? Formal logic is criticized and claimed to be inadequate because of its commitment to the soundness doctrine. In this paper I will examine and try to respond to some of these criticisms. It is not my aim to examine every argument ever given against formal logic; I am limiting myself to those that, as a matter of historical fact, were instrumental in the replacement of formal logic by informal logic and initially established informal logic as a separate discipline (in particular, Toulmin’s attacks on what he calls the “analytic ideal” will not form part of the discussion and were not instrumental in this way, only becoming appreciated later). If the criticism of the soundness doctrine is defective, then the move from formal logic to informal logic was not theoretically well-motivated. It is this motivation that I wish to bring into question, rather than the adequacy or inadequacy of formal or informal logic as such. While I will tend to the view that formal logic is as adequate as it is reasonable to expect, the real issue is whether it is inadequate for the reasons that, as a matter of historical fact, were used to motivate its rejection.     

Proof-Theoretic Functional Completeness for the Hybrid Logics of Everywhere and Elsewhere

A hybrid logic is obtained by adding to an ordinary modal logic further expressive power in the form of a second sort of propositional symbols called nominals and by adding so-called satisfaction operators. In this paper we consider hybridized versions of S5 (“the logic of everywhere”) and the modal logic of inequality (“the logic of elsewhere”). We give natural deduction systems for the logics and we prove functional completeness results.     

On Fork Arrow Logic and its Expressive Power

We compare fork arrow logic, an extension of arrow logic, and its natural first-order counterpart (the correspondence language) and show that both have the same expressive power. Arrow logic is a modal logic for reasoning about arrow structures, its expressive power is limited to a bounded fragment of first-order logic. Fork arrow logic is obtained by adding to arrow logic the fork modality (related to parallelism and synchronization). As a result, fork arrow logic attains the expressive power of its first-order correspondence language, so both can express the same input–output behavior of processes.     

The Logic and Meaning of Plurals. Part I

Contemporary accounts of logic and language cannot give proper treatments of plural constructions of natural languages. They assume that plural constructions are redundant devices used to abbreviate singular constructions. This paper and its sequel, “The logic and meaning of plurals, II”, aim to develop an account of logic and language that acknowledges limitations of singular constructions and recognizes plural constructions as their peers. To do so, the papers present natural accounts of the logic and meaning of plural constructions that result from the view that plural constructions are, by and large, devices for talking about many things (as such). The account of logic presented in the papers surpasses contemporary Fregean accounts in its scope. This extension of the scope of logic results from extending the range of languages that logic can directly relate to. Underlying the view of language that makes room for this is a perspective on reality that locates in the world what plural constructions can relate to. The papers suggest that reflections on plural constructions point to a broader framework for understanding logic, language, and reality that can replace the contemporary Fregean framework as this has replaced its Aristotelian ancestor.     

中国逻辑史视野下的先秦易学与名辩学

19世纪以来的中国逻辑史研究,比照西方逻辑,仅仅将先秦的名辩学看成是中国逻辑史的主要部分。其间虽有对《周易》的涉及,但也是浅尝辄止。本文从《周易》经、传产生的年代,特别是《周易》经、传所蕴涵的逻辑内容与先秦名辩逻辑的代表人物孔子、惠施、邓析等人的思想对比,说明先秦易学逻辑对名辩逻辑产生了深刻的影响。得出《周易》的经、传发轫了中国古代逻辑中的推类理论,而名辩学尤其是墨家辩学的推类理论则是对自《周易》以来的推类逻辑传统的总结和提高的结论。     

Logic and Metaphor

In this work, attention is drawn to the abundant use of metaphor and analogy in works of logic. I argue that pervasiveness of figurative language is to be counted among the features that characterize logic and distinguish it from other sciences. This characteristic feature reflects the creativity that is inherent in logic and indeed has been demonstrated to be a necessary part of logic. The goal of this paper, in short, is to provide specific examples of figurative language used in logic that yield insights into the nature of the subject. I encourage the reader to take metaphors seriously, and to accept that they are not mere embellishments but key elements in our understanding of logic.     

《逻辑学研究》征稿启事

《逻辑学研究》是中山大学和中国逻辑学会主办,由教育部高等院校人文社会科学重点研究基地中山大学逻辑与认知研究所承办的学术刊物,旨在积极推动我国逻辑学及相关学科的学术研究水平,增进海内外逻辑学及相关领域学术同行的交流。《逻辑学研究》是当前我国在逻辑学领域内唯一正式出版的专业刊物,采用中英双语发表论文。《逻辑学研究》目前为季刊,逢每季度第三个月的18日出版。自2011年起,中英文分开隔期出版《逻辑学研究》征稿的内容将主要包括下述方向:符号逻辑、非形式逻辑、逻辑与哲学、     

Deontic logic and the possibility of moral conflict

Standard dyadic deontic logic (as well as standard deontic logic) has recently come under attack by moral philosophers who maintain that the axioms of standard dyadic deontic logic are biased against moral theories which generate moral conflicts. Since moral theories which generate conflicts are at least logically tenable, it is argued, standard dyadic deontic logic should be modified so that the set of logically possible moral theories includes those which generate such conflicts. I argue that (1) there are only certain types of moral conflicts which are interesting, and which have worried moral theorists, (2) the modification of standard dyadic deontic logic along the lines suggested by those who defend the possibility of moral conflicts makes possible only uninteresting types of moral conflicts, and (3) the general strategy of piecemeal modification standard dyadic deontic logic is misguided: the possibility of interesting moral conflicts cannot be achieved in that way.     

从主体、结构到资本逻辑的结构化——反思关于马克思思想之研究模式的主导逻辑

自第二国际时代以来,关于马克思思想的研究在主导逻辑上经历了两次重要转换:一是上个世纪20年代以卢卡奇等为标志的从传统的经济决定论构架转向以主体-客体为核心的历史辩证法构架,这一研究直接影响到后来的西方马克思主义者,并在20世纪80年代以来的国内马克思思想研究中得到回应;二是在上个世纪50—60年代关于人与结构的逻辑论争中,以主体-客体为核心的历史辩证     

The natural history of the understanding: locke and the rise of facultative logic in the eighteenth century

Whatever its merits and difficulties, the concept of logic embedded in much of the ‘new philosophy’ of the early modern period was then understood to supplant contemporary views of formal logic. The notion of compiling a natural history of the understanding constituted the basis of this new concept of logic. The following paper attempts to trace this view of logic through some of the major and numerous minor texts of the period, centering on the development and influence of John Locke's understanding of the analysis of the cognitive faculties as the discipline of logic.     

Logical Foundations and Kant's Principles of Formal Logic

The abstract status of Kant's account of his ‘general logic’ is explained in comparison with Gödel's general definition of a formal logical system and reflections on ‘abstract’ (‘absolute’) concepts. Thereafter, an informal reconstruction of Kant's general logic is given from the aspect of the principles of contradiction, of sufficient reason, and of excluded middle. It is shown that Kant's composition of logic consists in a gradual strengthening of logical principles, starting from a weak principle of contradiction that tolerates a sort of contradictions in predication, and then proceeding to the (constructive) principle of sufficient reason, and to a classical-like logic, which includes the principle of excluded middle. A first-order formalisation is applied to this reconstruction, which reveals implicit modalities in Kant's account of logic, and confirms the implementability of Kant's logic into a sound and complete formal system.     

Aristotle's Prior Analytics and Boole's Laws of Thought

Prior Analytics by the Greek philosopher Aristotle (384?–?322 BCE) and Laws of Thought by the English mathematician George Boole (1815?–?1864) are the two most important surviving original logical works from before the advent of modern logic. This article has a single goal: to compare Aristotle's system with the system that Boole constructed over twenty-two centuries later intending to extend and perfect what Aristotle had started. This comparison merits an article itself. Accordingly, this article does not discuss many other historically and philosophically important aspects of Boole's book, e.g. his confused attempt to apply differential calculus to logic, his misguided effort to make his system of ‘class logic’ serve as a kind of ‘truth-functional logic’, his now almost forgotten foray into probability theory, or his blindness to the fact that a truth-functional combination of equations that follows from a given truth-functional combination of equations need not follow truth-functionally. One of the main conclusions is that Boole's contribution widened logic and changed its nature to such an extent that he fully deserves to share with Aristotle the status of being a founding figure in logic. By setting forth in clear and systematic fashion the basic methods for establishing validity and for establishing invalidity, Aristotle became the founder of logic as formal epistemology. By making the first unmistakable steps toward opening logic to the study of ‘laws of thought’—tautologies and laws such as excluded middle and non-contradiction—Boole became the founder of logic as formal ontology.

… using mathematical methods … has led to more knowledge about logic in one century than had been obtained from the death of Aristotle up to … when Boole's masterpiece was published.     

Moral conflict and the logic of rights

The paper proposes a revised logic of rights in order to accommodate moral conflict. There are often said to be two rival philosophical accounts of rights with respect to moral conflict. Specificationists about rights insist that rights cannot conflict, since they reflect overall deontic conclusions. Generalists instead argue that rights reflect pro tanto constraints on behaviour. After offering an overview of the debate between generalists and specificationists with respect to rights, I outline the challenge of developing a logic of rights-reasoning that is compatible with generalism. I then proceed to offer a new logical framework, which utilizes a simple non-monotonic logic of practical reasoning. Both generalist and specificationist interpretations of the logic are explored. The revised logic shows that traditional characterizations of the debate between specificationists and generalists obscure other relevant philosophical positions.

     

Logic and Ontology

A brief review of the historicalrelation between logic and ontologyand of the opposition between the viewsof logic as language and logic as calculusis given. We argue that predication is morefundamental than membership and that differenttheories of predication are based on differenttheories of universals, the three most importantbeing nominalism, conceptualism, and realism.These theories can be formulated as formalontologies, each with its own logic, andcompared with one another in terms of theirrespective explanatory powers. After a briefsurvey of such a comparison, we argue that anextended form of conceptual realism provides themost coherent formal ontology and, as such, canbe used to defend the view of logic as language.     

Routley Star and Hyperintensionality

Journal of Philosophical Logic - We compare the logic HYPE recently suggested by H. Leitgeb as a basic propositional logic to deal with hyperintensional contexts and Heyting-Ockham logic introduced...